1. Field of the Invention
The present invention relates to a gas temperature control apparatus for a DeNOx boiler in an engine cogeneration plant, which is installed to maintain a reaction temperature of denitrification catalyst used to remove nitrogen oxide generated from an internal combustion engine in the engine cogeneration plant. More particularly, the present invention relates to a gas temperature control apparatus for a DeNOx boiler in an engine cogeneration plant, which includes a connection passageway between a high-temperature gas part of a combustion tank of the boiler and an intermediate-temperature gas part formed after a first heat exchange, and a flow control valve mounted in the passageway, thereby controlling the volume of bypass combustion gas.
2. Background Art
In general, an internal combustion engine is a motor to move a piston with an expansive force of gas generated by burning and exploding fuel supplied in a cylinder. A boiler is an apparatus for heating water to generate vapor or warm water of high temperature and high pressure, and is mainly used in a heating facility or a bath room, or for driving a turbine, and so on.
As a prior art related with the present invention, U.S. Pat. No. 5,022,226 discloses a ‘system for low NO.sub.x cogeneration’, which includes an internal combustion engine, an electrical generator, an afterburner, a boiler, a catalyst bed, a fuel economizer, and a chimney.
Furthermore, Korean Patent No. 164,291 discloses a ‘burning apparatus for reducing nitrogen oxide (NOx) of a boiler’, which can control an air volume supplied from a combustion chamber of the boiler by a damper to thereby controlling generation of NOx, namely, one of harmful gases, generated by combination between nitrogen and oxygen.
Moreover, Korean Patent Laid-open No. 1998-051022 discloses a ‘bypass auxiliary catalytic converter’. In Korean Patent Laid-Open Publication No. 1998-051022, an exhaust pipe is connected to an inlet and an outlet of a main catalytic converter to bypass some of the gas discharged from an exhaust manifold.
However, in case of such prior arts have several problems, since it takes about two hours to raise temperature of water to a normal state and combustion gas of a low temperature state is introduced into a denitrification catalyst layer during the above time period, and hence, nitride oxide is not decomposed due to nonactivation of denitrification catalyst. Accordingly, the nitride oxide of high density discharged from the engine is discharged to the outside as it is, and hence, it causes air pollution and error actions of the system.